Passwords remembering problem

Is there any way to get Vivaldi to start remembering the password for a website, once it has been removed from the saved passwords list in settings?
I had instructed Vivaldi not to remember the password for a certain site, but later needed it to be remembered and filled automatically. I removed the site from the list of remembered passwords, assuming that this would cause Vivaldi to start re-prompting me when I login as to whether it should remember the password or not, but this didn't happen. Now Vivaldi never offers to remember the password, and I cant see any obvious way to add it back to the list manually.